Linder has worked with interest groups such as Americans for Fair Taxation as well as National Taxpayers Union. Since 1996 [11] Linder has backed the National Right to Life Committee 100 percent of the time. Since 1996 Linder has backed the U.S. Chamber of Commerce at least 90 percent of the time except in 2005 where he backed them 75 percent of the time. Throughout his career he has supported groups like National Small Business Association, National Association of Manufacturers, National Restaurant Association, and Small Business & Entrepreneurship Council. He also has backed the interests of the NRA throughout his career.[11]

A former dentist, Linder has received $40,100 from health professionals as well as $57,900 from the health sector as a whole. He also ran his own lending firm so he receives backing from the Insurance and Finance sector amounting to $86,839 as 12/31/2008.[12] He has received $25,401 from the Construction industry and $25,300 from the Energy and Natural Resources industry. Overall in the 2008 cycle he has a total income of $581,976 of which he spent $375,540, and by the end of the cycle he had accumulated no debt at all.[12]

Linder’s voting record is conservative. He has shown throughout his career that he is pro-life, voting for bills like Prohibit Partial-Birth/Late Term Abortion bill and Ban on Partial-Birth/Late Term Abortion.[13] He is also a fiscal conservative, voting against every piece of the stimulus package and most spending programs throughout his career, such as Auto Industry Financing, Funding to Combat AIDS, Malaria, and Tuberculosis, Housing Bill with Energy Tax Credit Extensions, Medicare Bill, and Public Transportation and Alternative Fuel Grants.[13]

Some have criticized Linder, Neal Boortz, and Americans For Fair Taxation for the way they have presented the FairTax plan, a tax reform that replaces all federal income taxes with a single national sales tax on personal consumption above poverty level. The most common critique is the method of presenting the FairTax rate as a 23% sales tax. Under the plan, consumers would pay to the government $23 out of every $100 (referred to as tax inclusive): items priced at $100 would contain $23 of taxes.[6] American sales taxes have historically been expressed as a percentage of the original sale price (referred to as tax exclusive): items produced at $77 pre-tax, cost $100 with the tax added (30% on top of $77).[14] Congressman John Linder has stated that the FairTax would be implemented as an inclusive tax, which would include the tax in the retail price, not added on at checkout—an item on the shelf for five dollars would be five dollars total.[7] The receipt would display the tax as 23 percent of the total.[5] Linder states the FairTax is presented as a 23 percent tax rate for easy comparison to income tax rates (the taxes it would be replacing). Proponents believe it is both inaccurate and misleading to say that an income tax is 23 percent and the FairTax is 30 percent as it implies that the sales tax burden is higher, when in fact the burden of the two taxes is precisely the same. The plan's opponents call the semantics deceptive.[14]FactCheck called the presentation misleading, saying that it hides the real truth of the tax rate.[15]

The FairTax has also been questioned by Social Security groups which believe the economic assumptions of the FairTax are unsound. The basis of the FairTax is that taxes affect economic decisions. The FairTax would remove all payroll taxes. Yet, the impact analysis of Social Security done by the FairTax supporters claims that the FairTax will not change the number of beneficiaries under existing law. Under economic principles normally applied by the Linder and Boortz, removing the cost of participation would increase not only the number of beneficiaries but the size of claims.

Linder has also been criticized for omitting a trip paid for by a client of lobbyistJack Abramoff from travel disclosure forms, even though he declared it on his personal income filings. According to John Byrne and Ron Brynaert of The Raw Story, "Linder should have filed a travel form shortly after his trip and could have corrected it when he belatedly filed for other trips last year. Failing to properly report sponsored travel is a violation of House rules."[16]

Georgia gained two seats after the 2000 census, but the Georgia state legislature produced a map intended to produce a congressional delegation of seven Democrats and six Republicans. Linder and fellow Republican Bob Barr were drawn into a heavily Republican district that, while retaining Barr's district number (the 7th), contained more of the territory Linder had represented in what had been the 4th District from 1993 to 1997 and the 11th District since 1997. Linder handily defeated Barr in the 2002 Republican primary, all but assuring him of a sixth term. Linder ran unopposed in 2004. In 2006, he was re-elected with 70.9% of the vote.[17]